1. Field of Invention
The invention relates to blood transfusion devices and more particularly to a safety blood transfusion device which can be disposed after use.
2. Description of Related Art
U.S. Pat. No. 6,569,116 to Wang is directed to an intravenous (IV) flow controlling device comprising a flexible open container having a specific gravity less than one and an outer diameter smaller than that of the drip chamber, the container including a spherical bottom portion thinner than the shell upper portion thereof; a first plastic tube coupled to the bottom of the container being in communication with the exit; a flexible reservoir having one end coupled to the first tube; and a second plastic tube coupled to the other end of the reservoir being in communication therewith. The container is submerged as fluid filled in the drip chamber. Fluid flows through the exit, the first plastic tube, the reservoir, and the second plastic tube to cause the container to fall, thereby stopping fluid exiting when the bottom portion of the container closes the exit and fluid in the drip chamber is used up. The reservoir is capable of being squeezed to force solution stored in the reservoir to reverse flow through the first tube to disengage the container from the exit. The device functions normally when solution is used up, abnormal solution dropping, drip chamber shaken, or drip chamber slanted.
The patent works well when the source is saline. However, it is no appropriate for blood transfusion as detailed below. In blood transfusion, red cells, plasma and platelets are separated into different containers and stored in appropriate conditions so that their use can be adapted to a patient's specific needs. Red cells work as oxygen transporters, plasma is used as a supplement of coagulation factors, and platelets are transfused when their number is very scarce or their function severely impaired. Platelets in the blood may coagulate to form clots which can adversely block the small bores of the tubes. This in turn can cause the IV flow controlling device to fail. Thus, the need for improvement still exists.